It has long been desirable to develop windows and glass products having light reflection and transmission properties that can be adjusted by an end user of the products. For example, adjustable tinting in a window would allow a user to increase light absorption, scattering, or reflection in the window at will, thereby reducing the amount of light that is transmitted through the window. Such a product could allow a user to adjust tint in order to suit privacy needs or total light needs, for example.
Conventional attempts at producing an adjustable tint window, however, have resulted in products with less than ideal characteristics. For example, windows using electrochromate oxidation reduction systems, or polymer disperse liquid crystal and suspended particle devices, can be very slow to convert from a non-tinted state to a tinted state after application of a voltage. This lag time is generally undesirable. Further, some conventional products have unacceptably high levels of haze. Additionally, conventional adjustable tint products can require the constant application of a voltage potential in order to maintain a tinted state, which both increases the complexity of use and cost, and limits the range of applications for the product.
Accordingly, further improved compositions and methods are needed to impart adjustable tint capability to polymer sheets and multiple layer glass products, and specifically to laminated glass panels comprising poly(vinyl butyral) layers and polyethylene terephthalate layers, so as to impart desirable, adjustable light transmission qualities on the finished glass panel.